Pretwisting apparatus for continuous filament yarns



11, 1966 E. COLOMBU ETAL 3, 77,

PRETWISTING APPARATUS FOR CONTINUOUS FILAMENT YARNS 2 Sheets-Sheet 1 Filed March 6, 1964 F/G. Z. 23 9 Inventors guGEN G ,quL lsP i Attorney Oct. 11, 1966 E. COLOMBU ETAL PRETWISTING APPARATUS FOR CONTINUOUS FILAMENT YARNS Filed March 6, 1964 2 Sheets-Sheet 2 I nventor Attorney trite In the process for transforming untwisted yarns comprising continuous filaments, notably of artificial or synthetic textiles, which are produced without twist, in the case of spinning on bobbins, a twist is imparted which is adapted to the applications for which these yarns are intended.

This twisting is generally divided into at least two successive phases. A first twist of 50 to 200 turns per metre, called a pretwist, is imparted, and thereafter the required twist is applied in one or more stages.

In order to impart the pretwist, the spinning bobbins are unwound onto bobbins, called spools without any twist being imparted, and the wound packages obtained are up-twisted, the twisted yarn being rewound onto cylindrical or conical bobbins. The up-twisting of the wound packages on spools generally takes place by means of uptwisting spindles. The yarn is taken up by the rewinding bobbin, which is driven by tangential contact with a driving roller, this take-up being theoretically constant. The speed of the driving roller bears a constant ratio to the speed of the spindles. Since the re- Winding speed depends in addition upon the twist which it is desired to obtain, attempts were first made to increase the speed of the spindles, and spindles were thereafter employed which gave at least two twists per spindle revolution. The use of the latter, however, requires that the yarn be taken up with extreme regularity in order to avoid breakage.

In addition, it is desirable to eliminate the intermediate unwinding onto spools which gives packages with small lap, which tend to form entanglements (due to broken filaments) in the twisting.

In the case of spindles giving two twists per spindle revolution, i.e. those giving a double twist in two successive phases, the twist produced is also more regular. The invention makes it possible to use wound packages coming from the spinning machine and to impart a twist of 50 to 200 turns per metre at a linear velocity of the order of 150 to 200 metres per minute which is compatible with the use of current precision winding machines.

The present invention consists in a combined apparatus comprising essentially per station:

(1) A spindle imparting two twists per spindle revolution,

(2) A supply element giving a predetermined take-up,

(3) A compensator which varies the rewinding speed of the yarn as a function of the variations of tension,

(4) A winding machine head whose linear velocity is modulated by the compensator, the spindle and the supply element being driven by a common motor.

Preferably, these devices are aligned side-by-side on a vertical base which may have one or two faces.

The invention will be more readily understood from a constructional example which, however, has no limiting character, the invention being intended to cover any variant in the same spirit. This constructional example is illustrated by the accompanying diagrammatic figures, in which FIG. 1 is an elevational view of a station embodying the invention; and FIG. 2 is a plan section taken along the line A-A' in FIG. 1.

In FIG. 1, the tubular uprights 1 and 2 and the tubular cross members 3, 4 and 5 constitute the frame of a bay containing the various parts of a station.

Mounted on the cross member 3 is a support plate 6 extending towards the corresponding cross member on the opposite side of the loom, or towards the corresponding cross member of the centre frame in the case of a double-faced loom. The cross member 4 at the centre of the frame similarly supports a plate 7. Secured below the plate is a motor 8 having a vertical shaft 8 which extends through the plate 7 to support a pulley 9. Close to the centre of the bay is vertically secured a spindle 10 giving two twists per revolution. This spindle is, for example, identical with that described in French Patent No. 982,134 granted January 12, 1949. The plate 7 also supports a supply element which is composed of a vertical spindle of axis 11 with a pulley 12.' The said spindle is coupled, for example by means of a helical worm gear (not shown) to the shaft of a supply cylinder 13. A small guide cylinder 14 is disposed at a short distance from the rim of the cylinder 13 with a slight inclination (which is not visible in the drawing) of its axis in relation to that of the cylinder 13 in accordance with a well known system.

Disposed on the plate 6 is a winder shown as a winding machine head 15 of the modulated type, having individual driving torque motor. Situated below the plate 6 is a guide roller 16 mounted on a rocking lever 17 having its pivot at 18. The said lever is drawn in three positions in dash-dotted lines and is associated with an electric compensator 18 of which the angular position determines the voltage across the terminals of the motor and thus the value of its torque, which has the effect of adjusting the speed of the motor so as to maintain constant the tension of the thread to be wound on.

A number of types of modulators are known. They may comprise a plunger-type solenoid, a rheostat, a voltage regulator, etc.

The upper tubular cross member 5 has mounted thereon the supports 19 and 20 of two guide rollers 21, 22 (see FIG. 2) with protecting members 23, 24 (see also FIG. 2).

The apparatus operates as follows:

The outer balloon 25 of the yarn unwound from the bobbin held fast within the barrel of the spindle 10 passes over a balloon guide 26, whereafter it passes over the guide rollers 21 and 22 and then in a number of parallel spiral turns over the assembly comprising the supply cylinder 13 and the guide member 14, the turns being continuously moved in well-known manner. The yarn thereafter travels around the roller 16 and becomes wound on the bobbin of the winding machine head 15.

If the tension of the yarn increases, the roller 16 and its support lever 17 are lifted, and conversely if the tension of the yarn decreases the roller and its support lever 17 are lowered.

The modification of the angular position of the lever 17 results in a modification of the torque of the motor controlling the winding machine head 15, thus compensating for the variation of the tension of the yarn.

The pulley 9, the whorl of the spindle 10 and the pulley 12 are connected by a belt 28, which also passes over an adjustable idler 27 (see FIG. 2).

Consequently, the motor 8 determines in a positive manner (apart from the slip of the belt 28) the speed of the spindle 10 and also the supply from the supply cylinder 13, which thus determines the total twist imparted by the spindle 10.

The take-up and consequently the twist may be modified by replacement of the pulley 12 of the supply cylinder 13 by a cylindrical pulley having a different diameter, which replacement may be readily and rapidly effected.

What is claimed is:

1. A pre-twisting apparatus for applying a twist to a yarn composed of a plurality of substantially untwisted continuous filaments comprising a double twist spindle adapted to apply a twist of two turns for each revolution of the spindle and having a driven spindle shaft to which a spool containing such untwisted filaments is fixed, means unwinding the filaments from said spindle in a manner to produce an external yarn balloon, a constant speed supply element, means feeding the yarn from said external ballon to said supply element, means driving said spindle shaft and said supply element at a constant predetermined speed ratio, a Winding member adapted to receive and wind the yarn from said supply element onto a yarn package, variable torque means for driving said winding member and a member responsive to variations in tension of the yarn between said supply element and said winding member connected to vary the torque of said winding member drive in a sense to maintain said yarn at a constant tension as it is wound onto said package.

2 Apparatus as set forth in claim 1 in which said variable torque drive means comprises an electric motor and said tension responsive member includes a rheostat connected to control the torque of said motor.

3. Apparatus as set forth in claim 1 in which said supply element includes a driven roll around which said yarn passes and drive means to drive said roll at a constant speed.

4. Apparatus as set forth in claim 3 in which the means to drive said roll and said spindle shaft are interconnected by a driving belt to be driven thereby at a fixed ratio.

5. Apparatus as set forth in claim 1 in which said tension control member comprises a pivoted arm carrying a roller around which said yarn passes in its path between said supply element and said winding member, said arm being shiftable in response to variations in yarn tension.

References Cited by the Examiner UNITED STATES PATENTS 2,969,197 1/1961 Weber et a1 242 4s X FOREIGN PATENTS 875,883 8/1961 Great Britain.

FRANK J. COHEN, Primary Examiner.

MERVIN STEIN, Examiner.

D. E. WATKINS, Assistant Examiner. 

1. A PRE-TWISTING APPARATUS FOR APPLYING A TWIST TO A YARN COMPOSED OF A PLURALITY OF SUBSTANTIALLY UNTWISTED CONTINUOUS FILAMENTS COMPRISING A DOUBLE TWIST SPINDLE ADAPTED TO APPLY A TWIST OF TWO TURNS FOR EACH REVOLUTION OF THE SPINDLE AND HAVING A DRIVEN SPINDLE SHAFT TO WHICH A SPOOL CONTAINING SUCH UNTWISTED FILAMENTS IS FIXED MEANS UNWINDING THE FILAMENTS FROM SAID SPINDLE INA MANNER TO PRODUCE AN EXTERNAL YARN BALLON, A CONSTANT SPEED SUPPLY ELEMENT MEANS FEEDING THE YARN FROM SAID EXTERNAL BALLON TO SAID SUPPLY ELEMENT, MEANS DRIVING SAID SPINDLE SHAFT AND SAID SUPPLY ELEMENT AT A CONSTANT PREDETERMINED SPEED RATIO, A WINDING MEMBER ADAPTED TO RECEIVE AND WIND THE YARN FROM SAID SUPPLY ELEMENT ONTO A YARN PACKAGE, VARIABLE TORQUE MEANS FOR DRIVING SAID WINDNG MEMBER AND A MEMBER RESPONSIVE TO VARIATIONS IN TENSION OF THE YARN BETWEEN SAID SUPPLY ELEMENT AND SAID WINDING MEMBER CONNECTED TO VARY THE TORQUE OF SAID WINDING MEMBER DRIVE IN A SENSE TO MAINTAIN SAID YARN AT A CONSTANT TENSION AS IT IS WOUND ONTO SAID PACKAGE. 